106 Polecat, Ferret, and Polecat-Ferret Hybrids 



erythristic mutations are known. In this variety the black pigment is 

 entirely suppressed, leaving the animal a beautiful reddish colour. 

 Erythrism is usually regarded as partial albinism, and in many species is 

 accompanied by absence of pigment from the eyes, but in the " red " 

 polecat the eyes are dark. The following is a good description of this 

 mutation. " The colour may be described roughly as : under fur light 

 buff, the longer hairy coat being a reddish-brown. When seen in sun- 

 light the latter shows a kind of faint purple 'haze,' it is difficult to 

 describe it otherwise." The writer, Mr F. S. Wright (4), adds that in all 

 the specimens examined by him the facial markings were normal, " but 

 owing to the lighter ground colour of the animal the contrast was 

 naturally not so great as in the common dark polecat"^. I can confirm 

 this from my own observation. 



Light brown polecats are only known from Cardiganshire, and chiefly 

 from the district around Aberystwyth, the greater number being recorded 

 from the neighbourhoods of Borth and Tregaron bogs. The first specimens 

 were made known in 1902-03(2), since when more than a dozen have 

 been killed. From this it seems that the form has originated compara- 

 tively recently in the locality mentioned, and that the mutation (for we 

 may safely assume it to be due to the loss of the black pigment factor) 

 far from tending to disappear is even on the increase. As all the red 

 polecats that have so far been recorded have been met with on the 

 Costal Plateau of Cardiganshire, an area which extends from the River 

 Dovey to Tregaron— about eighteen miles apart — it is evident that the 

 area, wherein we must seek the point of origination, is a comparatively 

 restricted one. As the first specimens were killed on Tregaron Bog it is 

 possible that this is the locality. As would be expected in the case of a 

 variation originating from the loss of a factor the reddish-brown colouring 

 gives us an example of simple Mendelian inheritance. The case is some- 

 what interesting however, as it is not very often that we get evidence of 

 the action of Mendel's law in wild Nature. Even in this case the infor- 

 mation is but scanty. In July, 1915, two young polecats of the same 

 litter, the one normal in colour, and the other red, were killed on Borth 

 Bog, " It is noteworthy that in the two offspring the colours show no 

 intermingling whatever " (4). Unfortunately there is no evidence to 

 show whether the light brown type is dominant or recessive, but judging 

 by a similar fawn-coloured variety of the ferret, presently to be described, 



1 Mr H. E. Forrest (2) has stated that the facial markings are sometimes suppressed in 

 this variety, but he now tells me {in litt. Feb. 16, 1920) that he is confident it was an error 

 due to the lessened conspicuousness of these markings on a light brown ground. 



